Synthesis, X-Ray Structure Determination and Related Physical Properties of Thiazolidinone Derivative by DFT Quantum Chemical Method.

In this paper we report the synthesis and characterization of the (Z)-3-N-(ethyl)-2-N'-((3-methoxyphenyl)imino)thiazolidine- 4-one by means of FT-IR, 1H and 13C NMR and by single crystal X-ray diffraction. The experimental determination of the crystal structure of the compound has been achieved using X-ray diffraction data. The important characteristic of the structure is the existence of a dihedral angle formed by the benzene and thiazolidinone rings being equal to 86.0° indicating an absence of α-α stacking as well as that the structure is non planar. In the crystal, the molecules are linked by C-H···O and C-H···N hydrogen bonds, these bonds being responsible for the three-dimensional molecular structure packing. In order to compare the experimental results with those of the theoretical calculation, quantum chemical DFT calculations were carried out using B3LYP/6-311G(d,p) basis set. In this context, the molecular electrostatic potential around the molecule and HOMO-LUMO energy levels were also computed. The dipole moment orientations were determined in order to understand the nature of inter- and intramolecular charge transfer. Finally, the stability of the title compound was confirmed throughout the calculation of the chemical reactivity descriptors.

Ni(II) complexes with 2,2-dipyridylamine and salicylaldehydes: Synthesis, crystal structure and interaction with calf-thymus DNA and albumins.

The synthesis of four cationic mixed-ligand Ni(II) complexes with 2,2'-dipyridylamine (dpamH) and substituted salicylaldehydes (X-saloH) was undertaken in an effort to discover new biologically active compounds. The complexes with the general formula [Ni(dpamH)2(X-salo)]Cl, 3-6, namely [Ni(dpamH)2(5-Cl-salo)]Cl, 3, [Ni(dpamH)2(5-Br-salo)]Cl, 4, [Ni(dpamH)2(5-CH3-salo)]Cl, 5, and [Ni(dpamH)2(3-OCH3-salo)]Cl·CH3OH, 6, were characterized by elemental analyses, FT-IR and UV-vis spectroscopy, magnetic and conductivity measurements. In addition, two analogous nickel-salicylaldehydato complexes in the absence of dpamH were prepared and characterized as [Ni(5-Cl-salo)2(CH3OH)2], 1 and [Ni(5-Br-salo)2(CH3OH)2], 2. The structures of complexes 1-6 were determined by X-ray crystallography revealing octahedral coordination of nickel (II) and monomeric nature of the compounds. Spectroscopic (UV-vis), electrochemical (cyclic voltammetry) and physicochemical (viscosity measurements) techniques were employed in order to study the binding mode and strength of the complexes to calf-thymus (CT) DNA, while competitive studies with ethidium bromide (EB), performed by fluorescence spectroscopy, revealed the ability of the complexes to displace the DNA-bound EB. The complexes bind to DNA probably via intercalation exhibiting high DNA-binding constants. For the cationic complexes 3-6, the coexistence of an electrostatic interaction with CT DNA may be also suggested. The interaction of the complexes with serum albumins was studied by fluorescence emission spectroscopy and the determined binding constants exhibit relative high values.

Zinc complexes of salicylaldehydes: synthesis, characterization and DNA-binding properties.

The neutral mononuclear zinc complexes with substituted salicylaldehydes, in the absence or presence of a nitrogen donor heterocyclic ligand 2,2'-bipyridine or 1,10-phenanthroline or 2,2'-dipyridylamine, have been synthesized and characterized by IR, UV and NMR spectroscopies. The experimental data suggest that salicylaldehyde is on deprotonated mode acting as a bidentate ligand coordinated to the metal ion through the phenolato and one aldehydo oxygen atoms. The crystal structures of bis(5-nitro-salicyladehydato)(2,2'-dipyridylamine)zinc(II), bis(5-chloro-salicylaldehydato)(2,2'-bipyridine)zinc(II) monohydrate and bis(5-bromo-salicyladehydato)bis(methanol)zinc(II) have been determined with X-ray crystallography. The ability of the complexes to bind to calf-thymus DNA (CT DNA) has been studied by UV and fluorescence spectroscopy and viscosity measurements. UV studies of the interaction of the complexes with DNA have shown that they can bind to CT DNA. The calculated binding constants of the complexes to DNA reveal tight binding to DNA. The complexes can probably bind to CT DNA via intercalation as concluded by studying the viscosity of a DNA solution in the presence of the complexes. Competitive studies with ethidium bromide (EB) have shown that the complexes can displace the DNA-bound EB suggesting strong competition with EB for the intercalation site of DNA.